Viscous silver halide photographid monobath solutions



United States Patent 3,392,019 VISCOUS SILVER HALIDE PHOTOGRAPHIC MONOBATH SOLUTIONS John C. Barnes and Gerald J. Johnston, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Continuation-impart of application Ser. No. 271,478, Apr. 8, 1963. This application Oct. 31, 1966, Ser. No. 590,473

23 Claims. (Cl. 96-61) This application is a continuation-in-part of our 00- pending application Ser. No. 271,478, filed Apr. 8, 1963, now abandoned.

This invention relates to photography and more particularly to viscous monobaths used for developing and stabilizing photographic silver halide emulsions.

Monobaths for processing photographic emulsions in a single bath have been proposed which would contain both the developing agent and the stabilizing or fixing agent in a single bath so that the photographic emulsion would be both developed and stabilized at the same time. Moreover, it has further been proposed that a single processing solution of the monobath type be prepared in a viscous condition so that it could be applied to the surface of a photographic emulsion in a rapid processing operation.

Monobaths are particularly useful in connection with Reader-Printers for microfilm in which the photographic light-sensitive paper is stored in the printer in roll form and copies are made from microfilm by exposing the sensitized paper to the desired subject matter and processin in a monobath. However, the monobath for a Reader-Printer should preferably be adequate to provide 20 prints per day for working days without exhaustion. The bath must withstand exposure to air during that time and must hold its complexed silver to prevent the formation of sludge or silver plating on the processor. The bath must provide satisfactory quality prints throughout the life of the bath and should withstand more than four weeks storage at 120 F. in a closed container. In addition, the bath should be stable at reduced temperature conditions so that it will remain in solution after at least 24 hours in a closed container at about 34 F. Moreover, clearing of the print must be relatively fast to provide copies in a short time.

When a monobath is to be used for rapid processing of motion picture film, particularly at high temperatures, the requirements for a satisfactory monobath are extremely stringent. Not only must the clearing rate be rapid, but the photographic quality of the image should be as good as that obtained by conventional processing.

The simple incorporation of the fixing compound, a water-soluble thiosulfate, in a developer solution containing a typical silver halide developer such as hydroquinone has an eifect on the photographic emulsion of decreasing the constrast and density and also producing undesirable silver sludge in the monobath, For these reasons, many other components have been proposed for use in monobaths along with components which increase the clearing rate of the photographic emulsion and result in low fog levels. For instance, the addition of development nuclei results in low fog levels and rapid clearing, but these nucleated particles tend to adhere to the surface of the emulsion. Amines have been suggested for use in monobaths, in order to provide increased speed and contrast. However, many amines cannot be used since they cause a loss in speed and contrast or excessive fog levels.

Other monobaths which have been proposed have resulted in considerable granularity due to the necessity for rapid development particularly at elevated temperatures and have been somewhat sensitive with respect to 3,392,019 Patented July 9, 1968 "ice temperature. In addition, the accumulation of bromide and iodide ions resulting from the processing reaction has limited the useful life of certain formulations. In some other instances, the use of components to improve certain characteristics of the processing bath has extended the processing time or raised the fog level.

Accordingly, it has been desirable to provide a monobath solution which would have the desirable processing characteristics obtained from conventional developing and stabilizing in separate operations. It has been especially desirable to provide a viscous monobath which could be used for rapid processing having these characteristics.

We have discovered a monobath combination containing three essential components in addition to the usual developer-stabilizing components which provide a synergistic result in obtaining the desirable characteristics in a viscous monobath. This combination comprises certain amine compounds together with physical development nuclei and a thickening agent.

One of the objects of this invention is to provide a viscous monobath containing a combination of at least one amine compound, physical development nuclei and a thickening agent. Another object is to provide a monobath having reduced processing time and an improved speedfog relationship. An additional object is to provide a monobath which results in reduced granularity in the silver halide emulsion and which has increased temperature latitude. A further object is to provide a monobath having minimized sensitivity to the accumulation of bromide and iodide ions resulting from processing reactions which will permit rejuvenation of the monobath. Another object is to provide a monobath having increased contrast and improved processing uniformity over previously known monobaths. Another object is to provide a method of processing exposed photographic elements employing a novel monobath. Additional objects will become apparent hereinafter.

The above objects are attained by incorporating physical development nuclei, a thickening agent and a particular amine compound in a monobath which comprises an aqueous alkaline solution containing a photographic de veloping agent .for reducing exposed silver halide to metallic silver and a water-soluble thiosulfate fixing agent in sufiicient quantity to stabilize substantially all unexposed silver halide.

The physical development nuclei are present in a concentration of from about 0.05 to about 2.0 grams per liter of monobath solution and can be any material suitable for this purpose and includes, for example, colloidal silver or the colloidal sulfides and selenides of the metals of group Ib, IIb, Nb and VIII of the Periodic Table including zinc, cadmium, nickel, silver, etc. Although the particle size is not particularly important to the operation of our monobath, the particles preferably have an average diameter of 72,500 A.

The thickening agent can be any material suitable for giving a desired viscosity to the monobath and includes, for example, a water-soluble polymer or gum such as guar gums, nonhydrolyzable cellulose esters such as carboxymethylcellulose or hydroxyethylcellulose, silica gel, starch, etc. Sufiicient thickening agent is used to produce a viscosity of at least about 50 cps., but not more than about 20,000 cps. at 24 C. The guar gums which can be used in this invention are mainly galactomannan. This material is a high molecular weight, carbohydrate polymer or polysaccharide made up of many mannose and galactose units linked together. In actual practice, the commercial product is obtained from guar and contains smaller quantities of protein, crude fiber and inorganic material.

. 3 The analysis of a typical guar gum is as follows:

Percent Galactomannan 78-82 Protein 7 4-5 Crude fiber 1.5-2.0 Ash 0.5-0.9

It will be appreciated that the term guar gum used herein and in the appended claims refers to the above compounds obtained from guar which may have a galactomannan content of from 50 to over 95 percent.

The amine compound can be either morpholine, a hydroxyalkyl amine containing a single hydroxyl group and wherein the hydroxyalkyl group has 1-5 carbon atoms, a sulfur dioxide addition product of morpholine or a sulfur dioxide addition product of said hydroxyalkyl amine. Another way of defining the hydroxyalkyl amine is the following general formula:

wherein R represents a hydroxyalkyl group having 1 to carbon atoms and R and R each represent a hydrogen atom or an alkyl hydrocarbon group having 1 to 3 carbon atoms. Typical amine compounds which can be used in the invention are, for example, Z-aminoethanol, 2- methylaminoethanol, 2-ethylaminoethanol, Z-dimethylaminoethanol, Z-diethylaminoethanol, or morpholine. A mixture of the amine and the sulfur dioxide addition product of the amine has also been found to give very good results. About /2-2 equivalents of amine per liter of monobath solution is a preferred concentration.

Any of the known black-and-white photographic developing agents can be used in the monobath of the invention. These developing agents can be employed alone or in combination such as, for example, a 3-pyrazolidone in combination with hydroquinone, N-methyl-p-aminophenol sulfate, chlorohydroquinone, etc. The concentration of the developing agent in the monobath composition can be varied, depending upon the particular photographic material undergoing development.

Another embodiment of the invention is to incorporate the photographic developing agents mentioned above into the photographic element itself so that the processing solution would then only contain a fixing agent, physical development nuclei, a thickening agent and the amine compound. In this embodiment, the developing agent may be incorporated directly into the emulsion layer or in a layer contiguous to the emulsion layer. The 3-pyrazolid0ne developing agents were found to be particularly useful for this application as were development precursors such as 3-acetoxy-1-phenyl-3-pyrazolidone.

The combination of hydroquinone with an auxiliary developing agent as set forth in the examples illustrates our preferred embodiment. It is desirable to use an auxiliary developer which increases the speed of the develop ing action. Any of the known auxiliary developers which increase the speed of hydroquinone as a developing agent may be used.

Typical auxiliary developing agents include those described in application Ser. No. 134,014, filed Aug. 25, 1961, of P. H. Stewart, G. E. Fallesen and I. W. Reeves, Jr., now abandoned. Auxiliary agents described in this application include 3-pyrazolidone compounds containing any alkyl (e.g., methyl, ethyl, etc.) or aryl substituent (e.g., phenyl, p-tolyl, etc.). In addition, such prazolidone developing agents can contain an acyl or acyloxy substituent which can be hydrolyzed from the 3-pyraz0lidone compound by treatment with an alkaline activator solution to produce the desired auxiliary developing compound. Typical auxiliary developing agents include, for example, 1 phenyl 3 pyrazolidone, 1 p tolyl-3-pyrazolidone, 1 phenyl 5 methyl 3 pyrazolidone, 1- acetamidophenyl-3-pyrazolidone, 3 acetoxyl-l-phenyl-3- pyrazolidone (enol ester), Z-(pyridinium acety1)-1- phenyl-3-pyrazolidone chloride, 1-phenyl-4,4-dirnethyl-3- pyrazolidone, l phenyl 2- laur0yl-3-pyrazolidone, lphenyl-Z-chloroacetyl-3-pyrazolidone, etc.

The concentration of auxiliary developing agents can be varied and, of course, no auxiliary developing agent need be employed unless so desired. Useful concentrations of auxiliary developing agents vary from about 0.005 mol to 0.5 mol per mol of developing agent. Depending upon the particular auxiliary developing agent employed, larger or smaller quantities can be used.

It will be appreciated that certain other developing agents can be used with the hydroquinone compounds of our invention provided theyhave the same speed as the combination of hydroquinone with an auxiliary developing agent of the type described above. The amount of silver halide developing agent can be varied widely depending upon the agent used and the particular silver halide emulsion. However, a preferred range is about between 1 to 20 grams per liter. It will also be appreciated that while in some instances a halide salt such as potassium iodide, potassium bromide, or the like is desirable, this is not a necessary component of the monobath. A water-soluble sulfite is desirable in the monobath in an amount at least sutficient to prevent preliminary oxidation of the developing agents, but may be omitted where the sulfur dioxide addition product of the amine is used.

The water-soluble thiosulfate fixing agent used in the monobath can be any of these suitable for the intended purpose and can be used in any quantity suificient to fix or stabilize substantially all of the unexposed silver halide. Suitable compounds include sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, etc. A particularly useful concentration for the thiosulfate compound was found to be at least about 20 grams per liter. The maximum concentration of the thiosulfate compound is primarily a function of the concentration of the silver halide in the emulsion being processed. Frequently, concentra tions as high as 200 grams of thiosulfate per liter of monobath composition can be employed and good quality images can be produced in 5 seconds or less usin such compositions. Of course, if the concentration of silver halide in the emulsion is increased, then it is possible that amounts of thiosulfate in excess of 200 grams per liter can be employed.

The pH of the monobath compositions of our invention can be varied, but especially useful results have been obtained at pHs of at least about 9.5 to pHs as high as about 12 or 12.5.

The silver halide emulsion of the photographic elements which can be processed in accordance with this invention may be sensitized using any of the well-known techniques in emulsion making, for example, 'by digesting with naturally active gelatin or various sulfur, selenium, tellurium compounds and/ or gold compounds. The emulsions can be sensitized with salts of noble metals of Group VIII of the Periodic Table which have an atomic weight greater than 100. The emulsions may also contain speed increasing addenda such as quaternary ammonium salts, polyethylene glycols or 'thioethe-r sensitizers.

The silver halide emulsion of the photographic elements which can be processed according to this invention may also contain conventional addenda such as gelatin plasticizers, coating aids, and hardeners such as alkali metal bisulfite-aldehyde addition products such as sodium formaldehyde 'bisulfi-te, glutaraldehyde bis(sodium bisulfite), beta-methyl glutaraldehyde bis(sodium bisulfite), maleic dialdehyde bis(sodium bisulfite) and the like. These emulsions may be useful in X-ray and other nonoptically sensitized emulsions, and may also be used in orthochromatic, panchromatic, and infrared sensitive emulsions. The addenda may be added to the emulsion before or after sensitizing dyes, if any are used. Sensitizing dyes useful in sensitizing such emulsions are decribed, for

example, in US. Patent 2,526,632 and 2,503,776. Spectral sensitizers which can be used are the cyanines, merocyanines, complex (trinuclear) cyanines, complex (trinuclear) merocyanines, styryls and hemicyanines. Various silver salts may be used as the sensitive salt such a silver bromide, silver iodide, silver chloride, or mixed silver halides such as silver chlorobromide or silver bromoiodide. The silver halides used can be those which form latent images predominantly on the surface of the silver halide grains or those which form latent images inside the silver halide crystals as exemplified by Davey and Knott US. Patent 2,592,250 as Well as direct positive emulsions such as those described in Kendall and Hill US. Patent 2,541,-

The silver halide emulsion layer of the photographic elements which can be processed according to the instant invention can contain any or the hydrophilic water-permeable binding materials suitable for this purpose. Suitable materials include gelatin, colloidal albumin, polyvinyl compounds, cellulose derivatives, acrylamide polymers, etc. Mixtures of these binding agents can also be used. The binding agents for the emulsion layer of the photographic element can also contain dispersed polymerized vinyl compounds. Such compounds are disclosed, for example, in US. Patents 3,142,568; 3,193,386; 3,062,- 67 4; and 3,220,844, and include the water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates and the like.

The silver halide emulsion of the photographic elements which can be processed according to the instant invention may be coated on a wide variety of supports. Typical supports are cellulose nitrate film, cellulose ester film, polyvinyl acetal film, polystyrene film, poly(ethylene terephthalate) film and related films or resinous materials as well as glass, paper, metal and the like. Supports such as paper which are coated with a-olefin polymers, particularly polymers of a-olefins containing two or more carbon atoms, as exemplified by polyethylene, polypropylene, ethylene-butene c-opolymers and the like can also be employed.

The following examples are intended to illustrate our invention but not to limit it in any way.

Example 1 Methyl'aminoethanol-sulfur dioxide addition product (17.8% S grams 75.0 1-phenyl-4,4-dimethyl-3 pyrazolidone do 2.0 Hydroquinone do- 10.0 Sodium thiosulfate crystal do 50.0 Potassium iodide do 0.5 P 10.5 Water to make 1.0 liter. Colloidal silver (Carey Lea Silver) "gram" 0.2 Natrosol (hydroxyethylcellulose) do 0.2

This monobath was appliedto the surface of an exposed silver bromoiodide emulsion, and after standing for minutes at70 F. was washed away to exhibit a very high quality, completely developed and fixed image. Photographic properties such as speed, contrast, granularity, and acutance are equal to those produced when this film is developed in the normal way using D-76 followed by separate fixation.

6 Example 3 Diethylaminoethanol-sulfur dioxide addition product (19% S0 grams 78.0 1-phenyl-3-pyrazolidone do 2.0 Hydroquinone do 10.0 Sodium thiosulfate crystal do 200.0 Colloidal silver (Carey Lea Silver) do 0.2 pH adjusted with KOH 10.5 Guar gum grams 11.0 Water t-o'make 1.0 liter.

Example 4 The above Examples 1, 2 and 3 were repeated substituting zinc sulfide, nickel sulfide, lead sulfide, silver sulfide, and copper sulfide as the nuclei in place of the colloidal silver. The monobaths provided the same high degree of photographic processing as were obtained using the colloidal silver.

Example 5 The following basic formula was prepared:

Sodium sulfite grams 30.0 1-Phenyl-3-pyrazolidone do 2.0 Hydroquinone do 10.0 Potassium bromide do 4.1 Potassium iodide do 0.32 Sodium thiosulfate-5H O -do 100.0 Hydroxyethyl cellulose do 0.2 Water to make 1.0 liter.

To this formula each of the following materials were added in the concentrations indicated:

Concen- Compound Classification tration equiv./ liter Sodium hydroxide Control 0.07 Sodium carbonate do 2-aminoetl1an01 Primary amine. 2-m ethylamlnoethanol Secondary amine 2,2-lmln0diethannl do Morpholine do 2-dlethylaminoethanol Tertiary amine 2,2,2-nitrilotriethanoL o Tetramethylarnmoniumbromide Quaternary amin V After addition, the pH was adjusted to 10.3 with sodium hydroxide in all cases. The series of monobaths was prepared in duplicate and Carey Lea Silver was added to one series at a concentration which resulted in 0.02 ram of silver per liter.

A silver bromoiodide emulsion was processed in each of the 18 monobaths for various times ranging from 1 to 16 minutes (with no agitation). This was accomplished in three dilferent ways:

(1) Unexposed film was processed in the monobath, was withdrawn when clear, and was then washed and dried without subsequent treatment. The amount of residual (unfixed) silver was then determined by analysis. These results were used to establish clearing rate data.

(2) Film which had been exposed to produce maxi.- mum density was similarly processed in the monobaths, was withdrawn when clear, and was then treated with a fixing solution to remove undeveloped silver halide. The amount of developed silver was determined by analysis.

(3) Film samples were expected through a step tablet on a Process Control Sensitometer and were processed in various monobaths for 16 minutes to insure completion of processing. Suitable exposures for evaluation of granularity and acutance were also processed.

RESULTS Substitution of sodium hydroxide for sodium carbonate caused an acceleration of clearing but did not strongly affect development rate.

The 2 -aminoethanol monobath exhibited a much higher clearing rate and a much higher development rate than did the sodium carbonate monobath. In this case, and in all subsequent cases, except with tetramethylammonium bromide, the concentration of the alkaline ingredients are nearly equivalent.

Very similar results were obtained with 2-methylaminoethanol. The various other amines did not all produce the same pattern of behavior, and they have been categorized in three basic groups based on their differences in behavior. The approximate rates of development and clearing were estimated from the slopes of the curves showing the growth of silver as a function of time, and clearing time was determined by visual observation.

Amine Clear- Rel. Rel. Compound Class ing Dev. Clear Group Time Rate Rate Sodium carbonate. 12 1 1 2-aminoethanol 6' 3. 8 3. I 2-methylamino-ethanol 2 6 3. 0 2. 9 I 2 diethylamino-ethanoL 3 7 4. 3 3. 5 I Morpholine 2 5 4. 2 3. 2 I 2,2-iminodiethanol 2 9 1. 7 1. 7 II Tetramethylammonium bromide 4 6' 2. 0 2. 9 II 2,2',2"-nitrilotriethanol 3 9. 5 1. 0 1. 5 III Sodium hydroxide 9.0 1. 0 1.4 III 1 Control.

The four amines in Group I increased both development rates and clearing rates, but appeared to proportionately increase development rate more than clearing rate. The two amines in Group II also increased both development and clearing rates, but did not increase the development rate significantly. The amine in Group III, as was also the case with sodium hydroxide, increased clearing rate and did not increase development rate. The pattern of behavior is not dependent upon the type of amine, i.e., whether primary, secondary, or tertiary, since samples of all three types are found in Group I.

The amines in Group I produced increases in density, while amines in Groups II and III produced decreases in density. This invention is thus concerned exclusively with amines of Group I. By dividing the relative development rate by the relative clearing rate and comparing the resultant ratios with the density levels produced at the most heavily exposed step, the following pattern is evident.

Ratio Rel. Dev. Rate/ Density Compound Rel. Clear Rate Sodium carbonate Z-aminoethanol 2-methylaminoethanol... 2-diethy1amin0ethano1 Morpholine 2,2-iminodiethanol Sodium hydroxide.--"

8 baths containing Carey Lea Silver is shown in the following table.

Compound Clearing Rel. Rel

In every case the addition of Carey Lea Silver caused a reduction in density; however, the relationships between the various types of amines remains the same as was the case in the absence of Carey Lea Silver. This may be seen from the following:

Ratio Compound Rel. Dev. Rate/ Density Rel. Clear Rate Sodium carbonate (no CLS) 1. 0 1. 62 Sodium carbonate (CLS) 0. 7 1. 27 2-amin0ethan 0. 3 1. 25 2-methylaminoethano1 0. 8 l. 24 2diethylaminoethanol... 0. 7 1. 30 Morpholine 0. 7 1. 32 2,2-iminodiethanol 0. 3 0. 87 Tetramethylammonium brom e 0. 4 0. 79 2,2',2-nitrilotriethanol O. 3 0. 88 Sodium hydroxide 0.3 0.98

A comparison of the above data shows the surprising result that the addition of the amines of Class I to monobath without added nuclei reduces the processing time (developing and fixing) from 12 minutes to 6 minutes. Similarly, the addition of the nuclei in the absence of the amine reduces the clearing time to one-half the control value. However, an even greater effect is discovered in the combination when both the nuclei and amine are present in the monobath. The processing time using the formulation of our invention is now reduced by a factor of four, so that just three minutes is required for complete processing instead of 12 minutes as for the control.

This monobath was used to process a low speed finegrain chlorobromide emulsion at F. After 15 seconds, the film is completely developed and cleared so that no residual silver halide remained. The minimum density in the clearest area was 0.6. This is too high for practical use.

To one liter of the above monobath, 1.0 gram of hydroxyethylcellulose was added so that the viscosity was increased to about 500 centipoises. A strip of the same film was processed under the same conditions in this thickened solution for 15 seconds. Processing was complete as in the previous example, but the minimum density was lowered .to 0.07. The significant lowering of the minimum density results in a negative comparable to one produced by a conventional processing.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A monobath composition for simultaneously developing and fixing an exposed photographic silver halide emulsion layer comprising an aqueous alkaline solution containing:

(a) a photographic developing agent for reducing exposed silver halide to metallic silver,

(b) a water-soluble thiosulfate compound in suflicient quantity to stabilize substantially all unexposed silver halide,

(c) physical development nuclei,

(d) sufiicient thickening agent so that the viscosity of the monobath is from about 50 to about 20,000 centipoises at 24 C., and

(e) an amine compound which is either morpholine, a hydroxyalkyl amine containing a single hydroxyl group and wherein the hydroxyalkyl group has 1-5 carbon atoms, a sulfur dioxide addition product of morpholine or a sulfur dioxide addition product of said hydroxyalkyl amine.

2. The monobath of claim 1 wherein said hydroxyalkyl amine has the following general formula:

wherein R represents a hydroxyalkyl group having lcarbon atoms and R and R each represents a hydrogen atom or an alkyl hydrocarbon group having 1 to 3 carbon atoms.

3. The monobath of claim 2 wherein said water-soluble thiosulfate compound is present in a concentration of at least about 20 grams per liter of solution, said physical development nuclei are present in a concentration of from about 0.05 to about 2.0 grams per liter of solution and said amine is present in a concentration of from about 0.5 to about 2.0 equivalents per liter of solution.

4. The monobath of claim 3 wherein said amine is 2- aminoethanol.

5. The monobath of claim 3 wherein said amine is Z-methylaminoethanol.

6. The monobath of claim 3 wherein said mine is Z-ethylaminoethanol.

7. The monobath of claim 3 wherein said amine is Z-dimethylaminoethanol.

8. The monobath of claim 3 wherein said amine is Z-diethylaminoethanol.

9. The monobath of claim 3 wherein said amine is morpholine.

10. The monobath of claim 3 wherein said thickening agent is either a guar gum, carboxymethyl cellulose, hydroxyethyl cellulose, silica gel or starch.

11. The monobath of claim wherein said thickening agent is carboxymethyl cellulose.

12. The monobath of claim 10 wherein said thickening agent is hydroxyethyl cellulose.

13. The monobath of claim 10 wherein said thickening agent is guar gum.

14. The monobath of claim 11 wherein said amine is a 2-methylaminoethanol-sulfur dioxide adduct and physical development nuclei are colloidal silver.

15. The monobath of claim 13 wherein said mine is a 2-diethylaminoethanol-sulfur dioxide adduct and said physical development nuclei are colloidal silver.

16. The monobath of claim 13 wherein said amine is Z-aminoethanol and said physical development nuclei are colloidal silver.

17. The monobath of claim 13 wherein said amine is Z-methylaminoethanol and said physical development nuclei are colloidal silver.

18. The monobath of claim 13 wherein said amine is Z-ethylaminoethanol and said physical development nuclei are colloidal silver.

19. The monobath of claim 13 wherein said amine is 2-diethylamin0ethanol and said physical development nuclei are colloidal silver 20. A composition for processing an exposed photographic element comprising at least one silver halide emulsion layer and said element containing a photographic developing agent for reducing exposed silver halide to metallic silver, said composition comprising an aqueous alkaline solution containing (a) at least about 20 grams of a water-soluble thiosulfate per liter of solution,

(b) 0.05 to about 2.0 grams of physical development nuclei per liter of solution,

(c) sufiicient thickening agent so that the viscosity of the solution is from about 50 to about 20,000 centipoises at 24 C., and

(d) an amine compound which is either morpholine, a hydroxyalkyl amine containing a single hydroxyl group and wherein the hydroxyalkyl group has 1-5 carbon atoms, a sulfur dioxide addition product of morpholine or a sulfur dioxide addition product of said hydroxyalkyl amine.

21. In a method of developing an exposed photographic silver halide emulsion layer using a monobath composition comprising a photographic silver halide developing agent for reducing exposed silver halide to metallic silver and sufficient water-soluble thiosulfate to fix substantially all unexposed silver halide, the improvement comprising adding to the monobath a small quantity of physical development nuclei; sufiicient thickening agent so that the viscosity of the monobath is from about 50 to about 20,000 centipoises at 24 C.; and an amine compound which is either morpholine, a hydroxyalkyl amine containing a single hydroxyl group and wherein the hydroxyalkyl group has -15 carbon atoms, a sulfur dioxide addition product of morpholine or a sulfur dioxide addition product of said hydroxyalkyl amine.

22. The process of claim 21 wherein said hydroxyalkyl amine has the following general formula:

wherein R represents a hydroxyalkyl group having 1-5 carbon atoms and R and R each represents a hydrogen atom or an alkyl hydrocarbon group having 1 to 3 carbon atoms.

23. The process of claim 22 wherein said water-soluble thiosulfate is present in a concentration of at least about 20 grams per liter of monobath, said physical development nuclei are present in a concentration of from about 0.05 to about 2.0 grams per liter of monobath, said amine is present in a concentration of from about 0.5 to about 2.0 equivalents per liter of monobath and said thickening agent is either a guar gum, carboxymethyl cellulose, hydroxyethyl cellulose, silica gel or starch.

References Cited UNITED STATES PATENTS 3,120,795 2/1964 Land 96-66 3,173,789 :3/1965 King et al. 96-61 3,179,517 4/1965 Tregillus et a1. 96-29 FOREIGN PATENTS 561,545 '10/ 1957 Belgium. 682,1 11 3/1964 Canada.

OTHER REFERENCES Mantell, C. L, The Water-Soluble Gums, New York, Reinhold Publishing Corporation, 1947, pp. 153-4.

The Condensed Chemical Dictionary, New York, Reinhold Publishing Corp., 1961, pp. 554, 593.

.T. TRAVIS BROWN, Acting Primary Examiner.

NORMAN G. TORCHIN, Examiner.

C. E. DAVIS, Assistant Examiner. 

1. A MONOBATH COMPOSITION FOR SIMULTANEOUSLY DEVELOPING AND FIXING AN EXPOSED PHOTOGRAPHIC SILVER HALIDE EMULSION LAYER COMPRISING AN AQUEOUS ALKALINE SOLUTION CONTAINING: (A) A PHOTOGRAPHIC DEVELOPING AGENT FOR REDUCING EXPOSED SILVER SHALIDE TO METALLIC SILVER, (B) A WATER-SOLUBLE THIOSULFATE COMPOUND IN SUFFICIENT QUANTITY TO STABILIZE SUBSTANTIALLY ALL UNEXPOSED SILVER HALIDE, (C) PHYSICAL DEVELOPMENT NUCLEI, (D) SUFFICIENT THICKENING AGENT SO THAT THE VISCOSITY OF THE MONOBATH IS FROM ABOUT 5/ TO ABOUT 20,000 CENTIPOSES AT 24*C., AND (E) AN AMINE COMPOUND WHICH IS EITHER MORPHOLINE, A HYDROXYALKYL AMINE CONTAINING A SINGLE HYDROXYL GROUP AND WHEREIN THE HYDROXYALKYL GROUP HAS 1-5 CARBON ATOMS, A SULFUR DIOXIDE ADDITION PRODUCT OF MORPHOLINE OR A SULFUR DIOXIDE ADDITION PRODUCT OF SAID HYDROXYALKYL AMINE. 